Fuse plug



Patented Dec. 28. 1926.

MYRON H. PATRICK, 0F SCHENECTADY, NEW YORK.

FUSE PLUG.

Application filed November 17, 1924. Serial No. 750,315.

This invention relates to an improved fuse plug, and it has more particularly reference to a device of this class which embodies a readily renewable fuse. v 7

It is my object to generally improve upon plugs of this class by providing one of extreme simplicity and durability, wherein a hollow cup-shaped plug is employed with a quickly renewable fuse located therein, there being a removable closing cap for the open end of the plug, permitting access to be had to the interior-for replacing the fuse.

Other features and advantages of the invention will become apparent from the following description and drawings.

In the accompanying drawing, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same:

.Figure 1 is a central vertical section, through a fuse plug constructed in accordance with the present invention.

Figure 2 is a top plan View thereof.

Figure 3 is a bottom plan view.

Figure L is a detail view of the renewable fuse, and

Figure 5 is a detail view of the fuse mounting element.

Referring to the drawing in detail, it will be seen that the fuse is composed mainly of a cup shaped body 1, which, in practice 1s preferably composed of hard rubber or 1ts equivalent. At its top, the body is surrounded by a flange 2, which is threaded around its periphery for purposes to be hereafter more fully described. The bottom of the body is formed with a central projection having a screw threaded socket for reception of ,a contact screw 3. Adjacent this projection is a recess 4, in which a small screw 5 is located. The screw 5 serves to clamp the inturned end of a metal shell 6 in place. The shell is threaded, in the usual way, for reception in the standard socket. The body is also provided, at diametrically opposite points with vertical bores havlng inturned lower ends, and a pair of substantially U-shaped brass strips 7, and 8, are located in these. The inner or lower inturned ends of the strips are connected with the screws 3 and 5 respectively. The upper inturnedends terminate in spaced relation, and constitute forksfor a renewable fuse designated generally 9. In the present instance, this renewable fuse. comprises an elongated piece of insulation 10 (see Figure 5) and a fuse link 11, (see Figure 4). The link is provided at its opposite ends with eyes 12, which register with openings 13, in the opposite ends of the fiber piece 10. This piece-or element is preferably provided between its ends with an outstanding tab 14. which constitutes a finger piece and is adapted to carr a mark indicating the amperage of the use link. The link may be secured to the fiber in any appropriate mannor, to provide a unit which may be more readily handled. Owing to the small size of the link, it will be otherwise inconvenient to handle.

The fuse unit so'made up is placed upon the inturned end of the brass strips 7 and 8, and screws 15 are passed through the registered openings to hold it in place.

A brass cap 16 is threaded upon the aforesaid flange 2 and has a central opening.

Held within the cap by a washer 17 is a mica disc 18, serving to protect and render the fuse visible.

In practice, the improved plug is used in the same manner as the ordinary plug, but it is advantageous thereover, because the fuse unit can be readily replaced if blown. Thus, instead of necessitating the provision of an entirely new plug, the removable cap is simply taken off and a new fuse is inserted. It may be said here that the small screw 5 serves to hold the shell against rotation relative to the body and the threads of the shell and body are opposite to the threads of the contact screw 3. This prevents unloosening of the last named screw, when removing or inserting the plug.

It is thought that the foregoing description will sufiice, when taken in connection with the accompanying drawing, to enable persons skilled in the art to which the invention relates to obtain a clear understandbeing provided with openings, means co-' operable with the opposite ends of said strips for conducting electricity therethrough, an elongated fiber'element rovided at its opposite ends with opemngs registrable with the openings in the intu'rned ends of said strips, said element being provided between its ends with a laterally directed finger-gripping tab, and a fusible link resting upon said fiber element and provided at its opposite ends with eyes registering with the openings in said'element, and connecting bolts passing through said eyes and through the openings in said element and inturned strip-ends, the latter together with said fiber element and fusible link and fastenings being located in the recess of said cups to render them accessible for replacement.

In testimony whereof I aflix my signature.

MYRON H. PATRICK. 

